Build Direction for Improved Process Plan in Multi-Material Additive Manufacturing

2014 ◽  
Author(s):  
Bashir Khoda
Keyword(s):  
Additive Manufacturing ◽  
Material Object ◽  
Layer By Layer ◽  
Multiple Features ◽  
Process Plan ◽  
Material Deposition ◽  
Heterogeneous Object ◽  
Build Time ◽  
Material Process ◽  
Manufacturing Techniques

Current additive manufacturing processes mostly accustomed with mono-material process plan algorithm to build object layer by layer. However, building a multi-material or heterogeneous object with an additive manufacturing system is fairly new but emerging concept. Unlike mono-material object, heterogeneous object contains multiple features or inhomogeneous architecture and can be decomposed into two dimensional heterogeneous layers with islands where each island represents associated feature’s properties. The material deposition path-plan in such multi-feature/multi-contour layers requires more resources and may affect the part integrity, quality, and build time. A novel framework is presented in this paper to determine the optimum build direction for heterogeneous object by differentiating the slice based on the resources requirement. Slices are bundled based on the heterogeneity and the effect of build directions are quantified considering the feature characteristics and manufacturing attributes. The proposed methodology is illustrated by examples with 50% or more homogeneous slices along the optimum build direction. The outcome would certainly benefit the process plan for multi-material additive manufacturing techniques.

Build Direction for 3D Heterogeneous Object in Additive Manufacturing

2013 ◽  
Author(s):  
AKM B. Khoda
Keyword(s):  
Additive Manufacturing ◽  
Object A ◽  
Support Materials ◽  
Part Quality ◽  
Material Deposition ◽  
Heterogeneous Object ◽  
Build Time ◽  
Functional Object ◽  
Continuous Material ◽  
Internal Architecture

Build direction in additive manufacturing is mostly determined considering the time, support materials and surface finish of the fabricated part. However, internal architecture of the part cannot be ignored in porous functional object design. Especially, heterogeneous object with internal features can be decomposed into 2D heterogeneous slices with island in which each island represent associated feature’s properties different from the base. Continuous material deposition in such multi-feature/multi-contour slices can be intervened by frequent directional changes intersecting those islands and can affect the build time and part quality. This research aims to minimize such intervention in the decomposed slices of heterogeneous object. A computational algorithm is proposed to quantify the build direction considering the location and alignment of the internal feature which can maximize the homogeneous slices generated from a heterogeneous object. The proposed methodology is illustrated by an example in this work. The algorithm can provide better control over the internal architecture design by selecting the best build direction for the heterogeneous object.

Increasing Part Accuracy in Additive Manufacturing Processes Using a k-d Tree Based Clustered Adaptive Layering

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Neeraj Panhalkar ◽  
Ratnadeep Paul ◽  
Sam Anand
Keyword(s):  
Additive Manufacturing ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Layer By Layer ◽  
Adaptive Slicing ◽  
Stl File ◽  
Build Time ◽  
Standard File Format ◽  
Aided Design ◽  
Profile Errors

Additive manufacturing (AM) is widely used in aerospace, automobile, and medical industries for building highly accurate parts using a layer by layer approach. The stereolithography (STL) file is the standard file format used in AM machines and approximates the three-dimensional (3D) model of parts using planar triangles. However, as the STL file is an approximation of the actual computer aided design (CAD) surface, the geometric errors in the final manufactured parts are pronounced, particularly in those parts with highly curved surfaces. If the part is built with the minimum uniform layer thickness allowed by the AM machine, the manufactured part will typically have the best quality, but this will also result in a considerable increase in build time. Therefore, as a compromise, the part can be built with variable layer thicknesses, i.e., using an adaptive layering technique, which will reduce the part build time while still reducing the part errors and satisfying the geometric tolerance callouts on the part. This paper describes a new approach of determining the variable slices using a 3D k-d tree method. The paper validates the proposed k-d tree based adaptive layering approach for three test parts and documents the results by comparing the volumetric, cylindricity, sphericity, and profile errors obtained from this approach with those obtained using a uniform slicing method. Since current AM machines are incapable of handling adaptive slicing approach directly, a “pseudo” grouped adaptive layering approach is also proposed here. This “clustered slicing” technique will enable the fabrication of a part in bands of varying slice thicknesses with each band having clusters of uniform slice thicknesses. The proposed k-d tree based adaptive slicing approach along with clustered slicing has been validated with simulations of the test parts of different shapes.

scholarly journals Taking into account thermal residual stresses in topology optimization of structures built by additive manufacturing

2018 ◽  
Vol 28 (12) ◽  
pp. 2313-2366 ◽  
Author(s):  
Grégoire Allaire ◽  
Lukas Jakabčin
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Residual Stresses ◽  
Heat Fluxes ◽  
Powder Layer ◽  
Layer By Layer ◽  
Thermal Deformations ◽  
Thermal Residual Stresses ◽  
Structural Design Optimization ◽  
Manufacturing Techniques

We introduce a model and several constraints for shape and topology optimization of structures, built by additive manufacturing techniques. The goal of these constraints is to take into account the thermal residual stresses or the thermal deformations, generated by processes like Selective Laser Melting, right from the beginning of the structural design optimization. In other words, the structure is optimized concurrently for its final use and for its behavior during the layer-by-layer production process. It is well known that metallic additive manufacturing generates very high temperatures and heat fluxes, which in turn yield thermal deformations that may prevent the coating of a new powder layer, or thermal residual stresses that may hinder the mechanical properties of the final design. Our proposed constraints are targeted to avoid these undesired effects. Shape derivatives are computed by an adjoint method and are incorporated into a level set numerical optimization algorithm. Several 2D and 3D numerical examples demonstrate the interest and effectiveness of our approach.

scholarly journals A review on integration of lightweight gradient lattice structures in additive manufacturing parts

2020 ◽  
Vol 12 (6) ◽  
pp. 168781402091695
Author(s):  
Asliah Seharing ◽  
Abdul Hadi Azman ◽  
Shahrum Abdullah
Keyword(s):  
Additive Manufacturing ◽  
Weight Ratio ◽  
Design Parameters ◽  
Layer By Layer ◽  
Lattice Structures ◽  
Unit Cells ◽  
Metallic Additive ◽  
Manufacturing Techniques ◽  
Future Work ◽  
Design Freedom

This review analyses the design, mechanical behaviors, manufacturability, and application of gradient lattice structures manufactured via metallic additive manufacturing technology. By varying the design parameters such as cell size, strut length, and strut diameter of the unit cells in lattice structures, a gradient property is obtained to achieve different levels of functionalities and optimize strength-to-weight ratio characteristics. Gradient lattice structures offer variable densification and porosities; and can combine more than one type of unit cells with different topologies which results in different performances in mechanical behavior layer-by-layer compared to non-gradient lattice structures. Additive manufacturing techniques are capable of manufacturing complex lightweight parts such as uniform and gradient lattice structures and hence offer design freedom for engineers. Despite these advantages, additive manufacturing has its own unique drawbacks in manufacturing lattice structures. The rules and strategies in overcoming the constraints are discussed and recommendations for future work were proposed.

Multiscale Modeling of the Laser Additive Manufacturing Process

2020 ◽  
pp. 235-248
Author(s):  
Seshadev Sahoo ◽  
Jyotirmoy Nandy
Keyword(s):  
Additive Manufacturing ◽  
Multiscale Modeling ◽  
Manufacturing Sector ◽  
Layer By Layer ◽  
Waste Production ◽  
Detailed Classification ◽  
Wide Range ◽  
Manufacturing Techniques ◽  
The Many ◽  
Efficient Manufacturing

Additive manufacturing (AM) has emerged as the most versatile process in the manufacturing sector. The advantages of AM such as applicability in a wide range of industries, ease of manufacturing, and reduction in waste production have increased its demand over the past decades. Out of the many techniques under AM, direct metal laser sintering (DMLS) is one of the most efficient manufacturing techniques that uses a high-powered laser beam to sinter metal powders in a layer-by-layer fashion. With the current usage of computational modeling, the prediction of microstructure evolution and other thermo-mechanical properties of different materials have been of great advantage to researchers. Along with a detailed classification of AM techniques, this chapter focuses on the use of continuum, phase field, and atomistic modeling under the DMLS process. The results show that multiscale modeling can be advantageous in gaining deeper insight into various phenomena like diffusion and sintering.

Thermomechanical Modeling of Additive Manufacturing Large Parts

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Erik R. Denlinger ◽  
Jeff Irwin ◽  
Pan Michaleris
Keyword(s):  
Energy Source ◽  
Additive Manufacturing ◽  
Material Properties ◽  
Degrees Of Freedom ◽  
Maximum Error ◽  
Layer By Layer ◽  
Material Deposition ◽  
Simulation And Experiment ◽  
Actual Material ◽  
Modeling Strategy

A finite element modeling strategy is developed to allow for the prediction of distortion accumulation in additive manufacturing (AM) large parts (on the order of meters). A 3D thermoelastoplastic analysis is performed using a hybrid quiet inactive element activation strategy combined with adaptive coarsening. At the beginning for the simulation, before material deposition commences, elements corresponding to deposition material are removed from the analysis, then elements are introduced in the model layer by layer in a quiet state with material properties rendering them irrelevant. As the moving energy source is applied on the part, elements are switched to active by restoring the actual material properties when the energy source is applied on them. A layer by layer coarsening strategy merging elements in lower layers of the build is also implemented such that while elements are added on the top of build, elements are merged below maintaining a low number of degrees of freedom in the model for the entire simulation. The effectiveness of the modeling strategy is demonstrated and experimentally validated on a large electron beam deposited Ti–6Al–4V part consisting of 107 deposition layers. The simulation and experiment show good agreement with a maximum error of 29%.

scholarly journals AVANCES EN EL DESARROLLO DE UN SISTEMA DE MANUFACTURA ADITIVA BASADO EN STEP-NC

2018 ◽  
Vol 4 (1) ◽  
pp. 39-53 ◽  
Author(s):  
Efrain Rodriguez ◽  
Renan Bonnard ◽  
Alberto José Alvares
Keyword(s):  
Additive Manufacturing ◽  
Manufacturing Systems ◽  
Manufacturing System ◽  
Reference Model ◽  
Object Oriented Programming ◽  
Numerical Control ◽  
Layer By Layer ◽  
Machining Processes ◽  
Material Deposition ◽  
Nc Program

The new standard of numerical control, known as STEP-NC, is categorized as the future of the advanced manufacturing systems. Greater flexibility and interoperability are some potential benefits offered by STEP-NC to meet the challenges of the new industrial landscape that is envisaged with the advent of Industry 4.0. Meanwhile, STEP-NC object-oriented programming has been partially applied and developed for machining processes (milling, turning...). But with the processes of additive manufacturing has not happened the same and the development is still incipient. This work presents the advances in the development of a new STEP-NC compliant additive manufacturing system, focusing particularly on the development of the information model. The application model activities in the IDEF0 nomenclature and application reference model in EXPRESS are presented. The AM-layer-feature concept has been introduced to define the manufacturing feature of additive processes based on material deposition layer-by-layer. Finally, a STEP-NC program generated from the EXPRESS model is presented, which can be implemented on an additive manufacturing system to validate the proposed model.                                                                                           

scholarly journals Iso-material contour representation for process planning of heterogeneous object model

2020 ◽  
Vol 7 (4) ◽  
pp. 498-513
Author(s):  
G K Sharma ◽  
B Gurumoorthy
Keyword(s):  
Additive Manufacturing ◽  
Material Composition ◽  
Composition Material ◽  
Object Model ◽  
Material Distribution ◽  
Process Plan ◽  
Contour Representation ◽  
Heterogeneous Objects ◽  
Raster Scan ◽  
Heterogeneous Object

Abstract Additive manufacturing is emerging as the preferred process for making heterogeneous objects. Planning the deposition of material is more complex for heterogeneous objects as the material variation has to be tracked along the path. This paper proposes an iso-material contour representation to generate the process plan for additive manufacturing given a smooth representation of heterogeneous object model. These contours represent the iso-material paths for deposition. As these paths shift along the direction of the gradation of material distribution, the deposition respects the gradient of the designed material distribution unlike iso-oriented paths generated by a raster scan method. Since the paths have the same material composition, material frequent change in the material composition is avoided, which, in turn, avoids the uneven deposition caused by the frequent start and stop of deposition while the material is being changed along the paths generated by the traditional raster scan. Associativity between the contours and the corresponding designed material feature is maintained, and therefore, changes in material composition are automatically propagated to the process plan.

Automated Planning for Robotic Multi-Resolution Additive Manufacturing

2021 ◽  
pp. 1-18
Author(s):  
Prahar Bhatt ◽  
Ashish Kulkarni ◽  
Rishi K. Malhan ◽  
Brual Shah ◽  
Yeo Jung Yoon ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Path Planning ◽  
Surface Quality ◽  
Computationally Efficient ◽  
Efficient Manner ◽  
Material Extrusion ◽  
Material Deposition ◽  
Build Time ◽  
Planning Algorithm ◽  
Path Planning Algorithm

Abstract Conventional material extrusion additive manufacturing (AM) processes require the user to make a trade-off between surface quality and build time of the part. The use of a large bead filament deposition can speed up the build process; however, it leads to surfaces with high roughness due to the stair-stepping effect. The surface quality can be improved by using a small bead filament deposition, which in turn increases the build time of the part. We present a new approach incorporating hybrid multi-resolution layers in material extrusion additive manufacturing to provide excellent surface quality without increasing the build time. Our slicing algorithm generates planar layers with large filament to fill the interior regions in less time. The generated exterior layers are conformal and use small filament to reduce the stair-stepping effect and improve surface quality. We also present a path planning algorithm to build parts with a single manipulator using a multi-nozzle extrusion tool. The path planning algorithm generates a smooth material deposition path by avoiding collision between the tool and the already built layers. It reduces the collision checks and performs collision detection in a computationally efficient manner. We build five parts to validate our approach and illustrate the benefits of multi-resolution AM.

Where Is the Missing Matter?

3D Printing ◽  
2017 ◽  
pp. 145-152
Author(s):  
Tihomir Mitev
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Industrial Revolution ◽  
Raw Materials ◽  
New Technology ◽  
Three Dimensional ◽  
Material Object ◽  
Layer By Layer ◽  
Solid Objects ◽  
Thing In Itself

The additive manufacturing (or the popular 3D printing) is relatively new technology which opens new spaces for entrepreneurial imagination and promises next stage of the industrial revolution. It is creating three dimensional solid objects from a digital file. The printer transforms the file into a material object layer by layer, using different raw materials. Today, the additive manufacturing is successfully used in architecture, medicine and healthcare, light and heavy industries, education, etc. The paper analyses the roles of actors in manufacturing the objects. It starts with the Heideggerian questioning of technology (), searching for the causes of bringing into appearance of the 3D model. According to Heideggerian analysis the technology is represented as an ‘unveiling of the truth'. The paper suggests that the old understanding of matter as a thing-in-itself should be replaced by a new, flexible, fluid, concept of matter, which is more or less manipulable. The matter is no more an occasion for object's taking place. On the other hand, it seems 3D printing technology is reduced to mere means; a simple intermediary, a copier of ideas. From that perspective the paper questioning the problem of action in ANT and search how action and interaction is distributed and how actors constitutes themselves as well as their actor-world.

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